GEOC 60 |
| Michael J. Pullin1, Charles Anthony2, and Patricia A. Maurice2. (1) Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, NM 87801, (2) Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, IN |
| Natural organic matter (NOM) is ubiquitous in aquatic environments, and it plays an important role in controlling many biogeochemical processes. Polyvalent metals such as Fe and Al are known to bind strongly to NOM and can also cause its coagulation. We also investigated the effects of Fe on NOM molecular weight, light absorbance, and fluorescence by adding increasing amounts of Fe(III) to aqueous solution of NOM isolate (0-10 uM) and following changes in these NOM properties. Absorbance at 254 nm was unchanged by added Fe, but was increased in the visible region (350-600 nm) and decreased in the far UV (200-225 nm), altering spectral slope. The fluorescence maxima observed for this sample decreased in intensity with increasing Fe, with no shift in peak location. Added Fe also increased the weight average molecular weight from 3661 Da to 3975 Da. These results have important implications for our understanding of the concept of 'molecular weight' as applied to NOM, and for NOM reactivity including bioavailability, adsorption, and other processes. |
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Chemistry of Metals in Terrestrial and Aquatic Systems
8:00 AM-11:30 AM, Tuesday, March 30, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |